The present invention relates to a process for producing a hollow molding, and more particularly, the invention relates to a process for continuously producing an irregular shaped hollow molding or a hollow molding which includes two portion having different cross-sectional configurations or different cross-sectional areas relative to each other.
The conventional process for producing the irregular shaped hollow molding comprises the steps of molding two hollow molding fractions having different cross-sectional configurations relative to each other, and fitting the fractions into bonding dies and bonding the fractions at the ends. Thus, since the conventional process for producing the irregular shaped hollow molding inevitably requires a step of bonding the molding fractions, the irregular shaped hollow molding as produced has a joining portion thereon.
A problem usually associated with the conventional process is that the produced irregular shaped hollow molding exhibits undesirable awkward appearance because of the joining portion formed thereon.
Another problem usually associated with the conventional process is that such a process require increased working time.
Japanese Laid-Open Patent Publication No. 62-121030 teaches a process for continuously producing an irregular shaped hollow molding in which the problems associated with the conventional process are effectively eliminated. The process, however, is not applicable when the two portions of the hollow molding are greatly different from each other in the cross-sectional configurations or cross-sectional areas.